Related Video: Believe It or Not, This Is a Dialect of English

I Say Twenty, You Say Jigger

But first, what's the difference between a language and a dialect? There is a famous answer to this question attributed to the linguist Max Weinreich: "A language is a dialect with an army and a navy." The point of this answer is not so much to say that all attempts to categorize or draw lines between languages and dialects are arbitrary, but to acknowledge that these lines take more than purely linguistic features into consideration. Power, prestige, and politics can bestow language status on a dialect. The standard language of France is based on the dialect spoken around Paris, the seat of power, while Provençal is considered a patois, or dialect. Speakers of Swedish and Norwegian may have very little difficulty understanding each other, but they live in different nations with different political institutions and are considered to be speaking different languages.

Certainly, linguistic features are important in determining whether two ways of speaking are seen as different languages or different dialects. If there is a lot of overlap in vocabulary and grammar, and if the speakers are reasonably intelligible to each other, we're most likely dealing with dialects. Speakers of American English, New Zealand English, and Scottish English varieties may have some trouble understanding each other, but even though all live in different nations (with their own armies and navies), they consider themselves to be speaking dialects of English.

In studies of bilinguals, improved cognitive performance has been found for people who speak languages quite different in grammar, vocabulary, and pronunciation, such as English and Japanese, but also for those who speak languages that are closer to each other, such as Spanish and Catalan. The study asked, why not take it a step further and see whether the effects would hold for tongues even closer to each other: dialects of the same language?

Initiate Code Switch

In Greek-speaking Cyprus, Standard Modern Greek is the official language, but the everyday language of life is Cypriot Greek, which differs from Standard Greek in pronunciation, vocabulary, and grammar. A team of researchers tested three groups of children on cognitive performance tasks: those who spoke only one language, those who spoke more than one language, and those who spoke more than one dialect of Greek. Both those who spoke more than one language and those who spoke more than one dialect performed better than those who only spoke one dialect of one language.

Why would speaking two dialects give the same advantages as speaking two languages? Modes of speaking, whether they're called languages or dialects, belong to communities of speakers, and it's usually the relative status of the community that determines whether they get to be called languages or dialects. But people can belong to many communities at once, and they can learn to easily "code switch" among many modes of speaking. In Greek-speaking Cyprus, people speak Cypriot Greek in casual life, but Standard Greek in the classroom, and in official or formal situations. They may make the switch back and forth many times a day.

The one-dialect group in the study were children from Athens, Greece who only spoke Standard Greek and whose parents also only spoke Standard Greek at home. These kinds of speakers do not have to do as much switching between different modes of speaking in the daily lives. It may turn out that the practice of switching, or managing many modes of speaking at once, regardless of how formal, official, or prestigious those modes of speaking are, is where the cognitive leg-up comes from.